Imaging with curved compression elements

ABSTRACT

A curved compression element, such as a breast compression paddle, and imaging systems and methods for use with curved compression elements. A system may include a radiation source, a detector, and a curved compression element. Operations are performed that include receiving image data from the detector; accessing a correction map for the at least one compression paddle; correcting the image data based on the correction map to generate a corrected image data; and generating an image of the breast based on the corrected image data. The breast compression element generally has no sharp edges, but rather has smooth edges and transitions between surfaces. The breast compression paddle also includes a flexible material that spans a portion of a curved bottom surface of the breast compression paddle to define a gap. The flexible material may be a thin-film material such as a shrink wrap.

CROSS-REFERENCE TO RELATED APPLICATIONS

This application is a continuation of U.S. patent application Ser. No.16/348,343, now U.S. Pat. No. 10,888,292, titled “Imaging with CurvedCompression Elements” and filed on May 8, 2019, which is a 371 of PCTInternational Application No. PCT/US2017/053311, titled “Imaging withCurved Compression Elements” and filed on Sep. 25, 2017, which claimspriority to: (1) U.S. Provisional Application No. 62/419,336, titled“Breast Compression Paddle” and filed on Nov. 8, 2016, and (2) U.S.Provisional Application No. 62/531,807, titled “Image Processing ForCurved Paddles” and filed on Jul. 12, 2017, both of which areincorporated by reference in their entireties.

BACKGROUND

A significant patient concern in mammography and breast tomosynthesis isthe discomfort the patient may feel when the breast is compressed,typically bet ween two rigid plastic surfaces, with sufficient force toimmobilize the breast and spread out the breast tissues for x-rayimaging. Another significant challenge is to ensure that the imagedfield include the desired amount of breast tissue. The reasons for usingcompression include: (1) to make the breast thinner in the direction ofx-ray flux and thereby reduce patient radiation exposure from the levelrequired to image the thicker parts of a breast that is not compressed;(2) to make the breast more uniform in thickness in the direction ofx-ray flux and thereby facilitate more uniform exposure at the imageplane over the entire breast image; (3) to immobilize the breast duringthe x-ray exposure and thereby reduce image blurring; and (4) to bringbreast tissues out from the chest wall into the imaging exposure fieldand thus image more tissue. As the breast is being compressed, typicallya technician manipulates the breast to position it appropriately andcounter the tendency that compression has of pushing breast tissuetoward the chest wall and out of the image field.

Standard compression methods for mammography and tomosynthesis use amovable, rigid clear plastic compression paddle. The breast is placed ona breast support platform that typically is flat, and the paddle is thencompressed onto the breast, usually while a technician or other healthprofessional is holding the breast in place and perhaps manipulates thebreast to ensure proper tissue coverage in the image receptors field ofview and to help spread the breast.

SUMMARY

In an aspect, the technology relates to a system for imaging a breast.The system includes a radiation source; at least one compression paddlehaving a non-planar compression surface, wherein the at least onecompression paddle is configured to compress the breast during imagingof the breast, a detector configured to detect radiation emitted fromthe radiation source after passing through the at least one compressionpaddle and the breast, wherein the detector includes a plurality ofpixels, and a memory and a processor operatively connected to thedetector, wherein the memory stores instructions that, when executed bythe processor, perform a set of operations. The operations includereceiving image data from the detector, accessing a correction map forthe at least one compression paddle, correcting the image data based onthe correction map to generate a corrected image data, and generating animage of the breast based on the corrected image data. In an example,the operations further include at least two of the following operations,upscaling the correction map based on an image size for the image;modifying the correction map by applying a squeeze factor; modifying thecorrection map for a projection angle and a paddle shirt; and modifyingthe correction map based on a magnification. In another example,modifying the correction map based on magnification is based at least inpart on a height of the compression paddle. In yet another example, thecorrection map is represented as a matrix, wherein the elements of thematrix represent correction values for a corresponding pixel of thedetector. In still yet another example, wherein the elements of thematrix include values for scaling a brightness value of thecorresponding pixel of the detector.

In another example, correcting the image data includes correcting theimage data on a pixel-by-pixel level. In yet another example, theoperations further include further correcting a chest-wall area of theimage representative of an area within about 2 cm of a chest wall. Instill yet another example, correcting the chest-wall area of the imageincludes determining a delta value based on at least a slope value and athreshold value.

In another example, the correction map is generated by a processincluding: filling the compression paddle with a liquid to create afilled paddle; placing the filled paddle on a substantially radiolucentsurface, wherein the radiolucent surface covers an imaging area of adetector, passing radiation through the filled paddle and substantiallyradiolucent surface, detecting the radiation passed through the filledpaddle and substantially radiolucent surface; generating a correctionimage based on the detected radiation, identifying an average pixelvalue over the correction image, and generating the correction map bydividing each pixel in the correction image by the average pixel value.In yet another example, generating the correction map further comprisesgenerating a series of polynomial fits to represent the correction map.

In another aspect, the technology relates to a method including: fillinga hollow paddle with a liquid to create a filled paddle; placing thefilled paddle on a substantially radiolucent surface, wherein theradiolucent surface covers an imaging area of a detector; passingradiation through the filled paddle and substantially radiolucentsurface, detecting the radiation passed through the filled paddle andsubstantially radiolucent surface; generating a correction image basedon the detected radiation, identifying an average pixel value over thecorrection image, and generating a correction map by dividing each pixelin the correction image by the average pixel value. In an example, themethod further comprises generating a series of polynomial fits torepresent the correction map. In another example, generating the seriesof polynomial fits comprises: for each image column (x) of the detector,selecting points along rows (y) of the detector; and fitting theselected points to a polynomial function to generate a set of fittedpoints; and wherein generating the correction map further includesgenerating a fitted image based on the fitted points In yet anotherexample, the polynomial function is a fourth-order polynomial. In stillyet another example, generating the correction map further comprises,smoothing the fitted image using a boxcar averaging method; and scalingdown the fitted image using decimation. In another example, the liquidis water and the substantially radiolucent material is a Lucite blockhaving a thickness of approximately 4 cm.

In yet another aspect, the technology relates to a computer-implementedmethod for generating an image of a breast. The method includesreceiving image data from a radiographic detector, accessing acorrection map for at least one compression paddle having a non-planarcompression surface, correcting the image data based on the correctionmap to generate corrected image data; and generating the image of thebreast based on the corrected image data. In an example, the methodfurther includes at least two of: upscaling the correction map based onan image size for the image; modifying the correction map by applying asqueeze factor, modifying the correction map for a projection angle anda paddle shift; and modifying the correction map based on amagnification In another example, the correction map is a matrix, andthe elements of the matrix represent correction values for acorresponding pixel of the detector. In yet another example, whereincorrecting the image data includes correcting the image data on apixel-by-pixel level.

In one aspect, the technology relates to a breast compression paddle foruse in an imaging system, the breast compression paddle having: a curvedright surface, a curved left surface; a curved bottom surface; a curvedfront surface; a top surface; and a flexible material in contact withthe curved tight surface, the curved left surface, the curved frontsurface, and the top surface, wherein the flexible material is spacedapart from at least a portion of the curved bottom surface.

In one aspect, the technology relates to a breast compression paddle foruse in an imaging system, the breast compression paddle having: a curvedright surface, a curved left surface, a curved bottom surface, a curvedfront surface, a top surface; and a transition between adjacent ones ofthe curved right surface, the curved left surface; the curved bottomsurface, the curved front surface, and the top surface, wherein alltransitions include no sharp edges.

In one aspect, the technology relates to an imaging system having: animaging source; an imaging receptor, and a breast compression elementhaving a plurality of curved side surfaces; a front surface connected toeach of the plurality of curved side surfaces with a smooth transitionbetween; a compression surface connecting the plurality of curved sidesurfaces; and a non-compression surface disposed opposite thecompression surface and connecting the plurality of curved sidesurfaces.

This summary is provided to introduce a selection of concepts in asimplified form that are further described below in the DetailedDescription. This summary is not intended to identity key features oressential features of the claimed subject matter, nor is it intended tobe used to limit the scope of the claimed subject matter.

BRIEF DESCRIPTION OF THE DRAWINGS

FIG. 1A depicts a perspective view of a portion of an upright breastx-ray imaging system.

FIG. 1B depicts a side elevation of ne system of FIG. 1A.

FIG. 1C depicts a side elevation of an example of a tilting imagingsystem.

FIG. 2 depicts a front elevation an imaging system showing rotationalmovement of a radiation source.

FIG. 3A depicts a top perspective view of a breast compression element.

FIG. 3B depicts a bottom perspective view of the breast compressionelement of FIG. 3A.

FIG. 3C depicts a front view of the breast compression element of FIG.3A.

FIG. 3D depicts a back view of the breast compression element of FIG.3A.

FIG. 3E depicts a right side view of the breast compression element ofFIG. 3A.

FIG. 3F depicts a left side view of the breast compression element ofFIG. 3A.

FIG. 3G depicts a top view of the breast compression element of FIG. 3A.

FIG. 3H depicts a bottom view of the breast compression element of FIG.3A.

FIG. 3I depicts an exploded perspective view of the breast compressionelement of FIG. 3A.

FIG. 4A depicts a schematic view of an imaging system using the breastcompression element of FIGS. 3A-3I.

FIG. 4B depicts a perspective view of an imaging system of FIG. 4A.

FIG. 5A depicts an example image without the image processing techniquesdiscussed herein.

FIG. 5B depicts an example image with the image processing techniquesdiscussed herein.

FIG. 6A depicts a method for generating a correction map for imageprocessing for curved paddles.

FIG. 6B depicts an example uncorrected image used for a samplecorrection map.

FIG. 6C depicts an example corrected image based on the samplecorrection map.

FIG. 7 depicts a method for image processing for curved paddles.

FIG. 8 depicts a method for image processing for a paddle providinginconsistent compression.

FIG. 9 depicts one example of a suitable operating environment in whichone or more of the present examples can be implemented.

FIG. 10 depicts an example of a network in which the various systems andmethods disclosed herein may operate.

DETAILED DESCRIPTION

The present technology relates to a breast compression element, such asa breast compression paddle or compression support surface, for use in abreast imaging system. During imaging of a breast, it is often desirableto immobilize the breast through compression. For instance, bycompressing the breast, the breast can be made thinner requiring a lowerdose of radiation. Further, by immobilizing the breast, image blurringfrom movement of the breast during imaging is reduced. Other benefitsare also realized by compressing the breast. The paddle commonly used tocompress the breast, however, may cause distortions in the imagingprocess as x-rays must pass through the paddle. For instance, while thecompression paddles are generally made from at least partiallyradiolucent materials, the shape and configuration of the compressionpaddles may cause deflection, refraction, dispersion, reflection, orother undesired interference with an x-ray beam as it passes through thepaddle. Thus, undesired artifacts may appear in the resultant image ormay need to be accounted for during image processing.

The puddle may also cause discomfort to the patient whose breast isbeing compressed. One reason for discomfort that the patient may fed isthat the compression force is non-uniformly distributed throughout thebreast. It is concentrated at the thickest portion of the breast,usually near the chest wall, at or near the lower front edge of thecompression paddle and the upper front corner of the breast platform.The anterior portion of the breast, such as near the nipple, may receiveless compressive force, or no compressive force. The paddle may not evencontact this portion of the breast. (The terms front, lower, and upperpertain to using a craniocaudal (CC) imaging orientation, with thepatient facing the front of the imaging system, although it should beunderstood that other imaging orientations, including mediolateraloblique (MLO) image orientations or views, are used with the sameequipment and these terms need to be adjusted accordingly.)

To improve these issues relating to compression elements, in part, thebreast compression elements discussed herein reduce or minimize sharpedges (e.g., no sharp edges), thus reducing image blurring due to edgeeffects. Further, the breast compression elements are shaped so as tohave a more consistent thickness at all angles during imaging.Additionally or alternatively, a thin material spans a curved bottomsurface of the breast compression element to create a gap between atleast a portion of the bottom surface and the thin material. Forexample, the thin material may be a flexible thin film materialdisplaying very limited stretching capability and strong tensilestrength. As the breast compression element is pressed against thebreast, the flexible material contacts the breast first so as to begincompression of the breast. As compressive pressure increases, theflexible material is deflected towards the curved bottom surface,providing a more comfortable compression process for the patent. Thedesign of the breast compression structure also allows for mine comfortand support in imaging systems that allow patients to tilt against thesystem.

FIGS. 1A-1C illustrate non-limiting examples of multi-mode breast x-rayimaging systems operable in a computed tomography (CT) mode but alsoconfigured to selectively operate in a tomosynthesis mode, including awide angle tomosynthesis mode and a narrow angle tomosynthesis mode, aswell as in a mammography mode. For clarity of illustration, a patientshield for use in the CT mode is omitted from FIGS. 1A-1B, but anexample is illustrated in FIG. 1C. A support column 100 is secured to afloor and houses a motorized mechanism for raising and lowering ahorizontally extending axle 102, which protrudes through an opening 100a in column 100, and for rotating axle 102 about its central axis. Axle102 in turn supports a coaxial axle 102 a that can rotate with orindependently of axle 102. Axle 102 supports a breast immobilizationunit comprising an upper compression element 104 a and a lowercompression element 104 b such that each compression element can move upand down along the long dimension of support 100 together with axles 102and 102 a. At least cue of the compression elements can move toward theother, and unit 104 can rotate about the common central axis of axles102 and 102 a. Either one or both of the upper compression element 104 aand the lower compression element 104 b may incorporate the breastcompression element discussed herein and shown in FIGS. 3A-3I. Thebreast compression element discussed herein is depicted in FIG. 1A as inthe upper position. In addition, axle 102 supports a gantry 106 for twotypes of motorized movement: rotation about the central axis of axle102, and motion relative to axle 102 along the length of gantry 106.Gantry 106 carries at one end an x-ray source such as a shrouded x-rayTube generally indicated at 108, and at the other end a receptor housing110 enclosing an imaging x-ray receptor.

When operating in a CT mode, the systems of FIGS. 1A-1C immobilize apatient's breast between compression elements 104 a and 104 b. Unit 104is raised or lowered together with axle 102 to the height of the breastwhile the patient is upright, e.g., standing or sitting. The patientleans toward unit 104 from the left side of the system as seen in FIG.1B, and a health professional, typically an x-ray technician, adjuststhe breast between compression elements 104 a and 104 b while pullingtissue to the right in FIG. 1B and moving at least one of compressionelements 104 a and 104 b toward the other to immobilize the breast andkeep it in place, with as much as practicable of the breast tissue beingbetween the compression elements 104 a and 104 b. In the course oftaking x-ray measurements representing CT projection x-ray images CTp,from which to reconstruct images CTr of respective breast slices, gantry106 rotates about the central axis of axle 102 while the breast remainsimmobilized in unit 104. Imaging x-ray receptor 112 inside housing 110may remain fixed relative to x-ray tube 108 during the rotation ofgantry 106. In another example, the x-ray receptor 112 may rotate orpivot within the housing 110. A pyramid shaped beam of x-rays from tube108 traverses the breast immobilized in unit 104 and impinges on imagingreceptor 112, which in response generates a respective two-dimensionalarray of pixel values related to the amount of x-ray energy received foreach increment of rotation at respective pixel positions in an imagingplane of the receptor. These arrays of pixel values for images CTp aredelivered to and processed by a computer system to reconstruct sliceimages CTr of the breast. Gantry 106 may be configured for motorizedmovement toward column 100, to facilitate the x-ray technician's accessto the patient's breast for positioning the breast in unit 104, and awayfrom column 100 to ensure that x-ray tube 108 and imaging receptor 112inside housing 110 can image the appropriate breast tissue.Alternatively, gantry 106 can maintain a fixed distance from column 100,to the left of the position seen in FIG. 1A, so that the imaging x-raybeam can pass through as much as practical of the breast immobilized inunit 104, in which case there would be no need for a mechanism to varythat distance.

FIG. 1C includes many of the same elements, components, andfunctionality as the example depicted in FIGS. 1A and 1B. Additionally,FIG. 1C includes a column 1000 that pivots from a vertical positionabout a pivot axis 1001 of a pivoting support 1002. for example over anangle α as illustrated. The angle α may be up to about 5°, up to about10°, up to about 15°, or higher. This pivoting allows the patient tolean forward against a shield 1004, which may increase patient comfortand protect the patient from the rotating components. A rotating C-arm1006 can carry an x-ray source 108 emitting x-ray beam 109, and an x-rayimaging receptor housing 110, and can be moved up and down column 1000to accommodate patients of different heights. Shield 1004 shields thepatient from the x-ray source 108 as it rotates around breastcompression unit 104, and also shields the patient from any rotation ofx-ray imaging receptor housing 110 containing an imaging receptor 112.Shield 1004 further acts to stabilize the patient leaning against it,and may include handles that the patient may hold to further facilitatepatient comfort and stability. Shield 1004 can surround the rotationaltrajectory of source 108 and housing 110, and may include a frontportion 1004 b that has an opening for the patient's breast, whichopening may be sufficiently large to allow a health professional toreach in to adjust the breast as it is being compressed. Shield 1004 asurrounds compression unit 104 that may include two compression elements101 a, 101 b, as discussed above. Shield 1004 a may also include aportion 1004 b that also protects the patient from motion of gantry1006. Some or all of portion 1004 b may be removable, particularly fortaking mammograms. Further, as the patient leans against the imagingsystem, the patient also directly applies her weight against the breastcompression unit 104.

FIG. 2 depicts a front elevation an imaging system showing rotationalmovement of a radiation source CT scanning typically involves a rotationof the source 110 and receptor 108 through an angle of about 180° plusthe angle subtended by the imaging x-ray beam, and in certain examples arotation through a greater angle, e.g., about 360°, as shown in FIG. 2 .Tomosynthesis scans similarly involve rotation of the source 110,although generally across a smaller angle, such as about 15°. The source110 and receptor 108 rotate mound breast about the central axis of theaxle 102. The path along which the source 110 and the receptor 108rotate may be called an imaging arc 116. The imaging arc 116 has aradius R_(I) that extends from a center point C_(I) which is located atthe central axis of the axle 102 to the source, such as the x-ray tube108. As such, a simplified representation of the of curvature (k_(I)) ofthe imaging arc 116 is 1/R_(I). In practice, the rotation may only beperformed over a portion of the imaging arc 116, but the radius R_(I),center point C_(I), and curvature (k_(I)) of the arc 116 remains thesame. Another position of the source 110′ and the receptor 108′ aredepicted in FIG. 2 for illustrative purposes.

As discussed above, a challenge in upright breast CT and/ortomosynthesis is how to immobilize the breast. In some cases, forvarious reasons, little or no compression of the breast may bedesirable. In other cases, it may be desirable to compress or otherwiseact on the breast, for example so that breast tissue can be pulled awayfrom patients chest wall and securely retained in unit 104 for imaging.Accordingly, and to generally increase patient comfort, one or both ofcompression elements 104 a and 104 b are shaped in a manner designed tohold the breast for CT and/or tomosynthesis imaging while keeping thebreast shaped so as to allow for close to equal path lengths of x-raysat least within individual slices. For example, the compression elements104 a and 104 b may have, on the compression surfaces of the elements104 a, 104 b, a curvature in the shape of an arc that shares the samecenter point C_(I) as the imaging arc 116. This curvature is depictedmore clearly in FIG. 3C. In such an example, the arc of the compressionsurface and the imaging arc 116 are concentric. In another example, thecurvature of the compression surfaces of the compression elements 104 aand 104 b substantially matches the curvature of the imaging arc 116. Insome examples, the curvature of the compression surfaces may be greaterthan or less than the curvature of the imaging arc 116. Compressionelements 104 a and 104 b may be removably secured via a bracket so thatdifferent sets of compression elements can be used to accommodatedifferently sized or shaped breasts. Different degrees of breastcompression can be used as selected by a health professional operatingthe systems described herein.

An example of a breast compression element 300 is shown in multipleviews shown in FIGS. 3A-3I. FIGS. 3A-3I are described concurrently. Thebreast compression element 300 may be utilized as a breast compressionpaddle or surface or a breast support platform. In general, surfaces ofthe breast compression element 300 are described as depicted in thefigures (e.g., “top,” bottom,” “left,” etc.). These general terms areutilized for clarity only to distinguish the various surfaces from eachother. For instance, in FIGS. 3A-3I, the compression surface may bereferred to as the bottom surface 318 and the non-compression surfacemay be referred to as the top surface 308. The breast compressionelement 300 includes a curved front surface 302, a curved left surface304, a curved right surface 306, a top surface 308, a back surface 310,and a curved bottom surface 318. The breast compression element 300 maybe manufactured from a material that is designed to cause minimalinterference with the radiation beam passing through the breastcompression element 300, such as a radiolucent material. For example,the breast compression element 300 may be made from a polycarbonatematerial, a carbon fiber material, or other similar materials. Thebreast compression element 300 may be hollow, solid, or partiallyfilled. The back surface 310 of the breast compression element 300 isattached to a bracket 312. The bracket 312 may then be removablyattached to an imaging system, as discussed above. The bracket 312and/or a surface of the compression element 300 may have a gas inletport 313 that is in fluidic communication with an interior of thecompression element 300. Heated fluid, such as warm air or gas, may beinjected into the compression element 300 via the gas inlet port to warmthe compression element 300 before and/or during contact with thebreast. Certain compression elements 300 may define a plurality of portsto allow the fluid to escape into a gap 316 between a flexible material314 and the more rigid structure of the breast compression element 300.

In some implementations, the breast compression element 300 issurrounded by a flexible material 314. The flexible material 314 isgenerally a thin-film material and may be made from a variety ofmaterials, e.g., a shrink-wrap material. In some examples, the flexiblematerial 314 has a high tensile strength and limited stretchingcharacteristics when surrounding the breast compression element 300. Inan example, the flexible material 314 is in contact with and surroundsthe right surface 306, the left surface 304, and the top surface 308. Insuch an example, the flexible material 314 spans from the right surface306 to the left surface 304, defining a gap 316 between the flexiblematerial 314 and the bottom surface 318. For instance, the flexiblematerial 314 is spaced apart from the concave bottom surface 318 todefine the gap 316. When the flexible material 314 spans from the rightsurface 306 to the left surface 306, the flexible material 314 istensioned such that the portion of the flexible material 314 spacedapart from the concave bottom surface 318 is less flexible then when ina non-tensioned state, but without being rigid. In some examples, theflexible material 314 also surrounds the curved front surface 302. Theflexible material 314 may also surround at least a portion of the backsurface 310.

In operation, the breast compression element 300 is pressed against thebreast such that the flexible material 114 first contacts the breast. Inone embodiment, as the breast compression element 300 continues tocompress the breast, the breast forces the flexible material 314 closerto the bottom surface 318 until the flexible material ultimatelycontacts the bottom surface 318, thus eliminating the gap 316. By havingthe flexible material 314 first contact the breast, patient comfort mayincrease and a more uniform compression may be achieved as the flexiblematerial 314 contours to the shape of the breast during compression.

The shape of the breast compression element 300 also provides additionalbenefits in imaging systems. As can be seen from FIGS. 3A-3I, the breastcompression dement 300 is substantially symmetric about plane S, shownin FIG. 3G. The left surface 304 and the right surface 300 are generallysemicylindrical. The height H_(S) of the semicylindrical shape of theleft surface 104 and the right surface 106 is defined by the backsurface 110 and the beginning of the front surface, as shown in FIG. 3G.The semicylindrical shape of the left surface 304 and the right surface306 has a radius R_(S), as shown in FIG. 3C. In some examples, theradius R_(S) is between about 1-2 inches. In other examples, the radiusR_(S) is between about 1.2 to about 1.8 inches. In yet further examples,the radius is R_(S) is between about 1.4 to about 1.6 inches.

The front surface 302 is shaped substantially as two half hemispheresconnected by a partial semicylinder. One of the half-hemispheres isattached to the front of the left surface 304 and the otherhalf-hemisphere is attached to the right surface 306. In some examples,the radius of the half-hemispheres R_(H) is the same as the radius R_(S)of the semicylindrical shape of the left surface 304 and the rightsurface 306, as shown in FIG. 3C. The two half-hemisphere shapes areconnected by a partial semicylinder having a height H_(P) defined bydistance between the front-most points of the two half-hemisphere shapesof the front surface 302, as shown in FIG. 3C. The partial semicylinderhas a curved surface, which forms the front edge of the bottom surface318. Because of the curved surface of the partial semicylinder, thepartial semicylinder has a variable radius R_(P), with its maximumradius R_(Pmax) occurring at the inner edges of the two half-hemisphereshapes and its minimum radius R_(Pmin) occurring at the geometric centerof the front surface 302, as shown in FIG. 3C.

The bottom surface 318 is a curved substantially smooth surface in theshape of an arc. As discussed above, the center point C_(B) of thebottom surface 318 arc may be the same as the center point C_(I) of theimaging arc. In such an example, the arc of the bottom surface 318 isconcentric with the imaging arc. In another example, the curvature(k_(B)) of the bottom surface 318 may be equal to the curvature (k_(I))of the imaging arc. In that example, the curvature (k_(B)) of the bottomsurface 318 is equal to the inverse of the arc radius R_(B) of thebottom surface 318. In some examples, the curvature (k_(B)) of thebottom surface, may be greater than or less than the curvature (k_(I))of the imaging arc. For instance, the ratio of the curvature (k_(B)) ofthe bottom surface to the curvature (k_(I)) of the imaging arc may beabout 5:1 or greater. The bottom surface 318 is connected to the leftsurface 304, the right surface 306, the back surface 310, and the frontsurface 302.

The top surface 308 is a substantially planar surface connected to theleft surface 304, the right surface 306, the back surface 310, and thefront surface 302. In other examples, the top surface 308 may be acurved surface having a shape similar to the curved bottom surface 318.For instance, the top surface 308 may be arc-shaped with a center pointof the top surface 308 arc being the same as the center point C_(I) ofthe imaging system and the center point C_(B) of the bottom surface 318.In such an example, the imaging are, the arc of the top surface 308, andthe arc of the bottom surface 318 are all concentric. Thus, thethickness of the compression element 300 remains consistent for a largerportion of the breast compression element 300 relative to the imagingsource as it sweeps across the imaging arc. In other examples, the topsurface 308 may have a curvature (k_(T)) equal to that of the curvature(k_(B)) of the bottom surface 318 and/or the curvature (K_(I)) of theimaging arc.

The compression element 300 is substantially free from sharp edges. Forexample, the transitions between the surfaces of the compression element300 may all be smooth and therefore free from sharp edges. Thetransition between the left surface 304 and the top surface 308 occursat the location where the tangent plane to the semicylindrical shape ofthe left surface 304 intersects and is parallel to the plane of the ofthe top surface 308. Similarly, the transition between the right surface306 intersects and the top surface 308 occurs at the location where thetangent plane to the semicylindrical shape of the right surface 306 isparallel to the plane of the of the top surface 308. The transitionbetween the front surface 302 and the top surface 308 occurs where thetangent planes of the half-hemisphere shapes and the partialsemicylinder shape of the front surface 302 intersect and are parallelwith the plane of the top surface 308. The transitions between the frontsurface 302 and the left surface 304 and the right surface 306,respectively, also occur at locations where the tangent plane of thesemicylindrical shapes of the left surface 304 and the right surface 306intersect and are parallel to the tangent planes of the half-hemisphereshapes of the front surface 302. Further, the transition between thefront surface 302 and the bottom surface 318 occurs at a location suchthat the curvature of the bottom edge of the front surface 302 matchesthe curvature of the bottom surface 318. The transition between thefront surface 302 and the bottom surface 318 is also at a location wherethe tangent plane of the partial semicylinder shape of the front surfaceis parallel to the tangent plane of the curved bottom surface 318. Thetransitions between the bottom surface 318 and the left surface 304 andthe right surface 306, respectively, also occur at locations where thetangent plane of the semicylindrical shapes of the left surface 304 andthe right surface 306 intersect and are parallel to the tangent planesof the curved bottom surface 318. Accordingly, each those transitionsare smooth and do not include any sharp edges.

The smooth surfaces and transitions between the surfaces provide foradditional comfort of the patient and improved image quality. Forinstance, the smooth curved bottom surface 318 allows for a morecomfortable compression procedure for the patient. The smoothtransitions between the surfaces also increase the comfort of thepatient, particularly in systems that involve tilting of the imagingsystem, such as depicted in FIG. 1C. In such systems, the chest wall ofthe patient is pressed against the from surface 302 of the compressionelement 300 could cause significant discomfort. The structure of thecompression element 300 is also suited to support the weight of thepatient that is applied to the compression element 300 during scanningin a tilted system.

The transitions between adjacent surfaces are described herein as smoothand substantially free from sharp edges. Sharp edges may cause areas ofhigh stress on the shrink wrap that covers a significant portion of thebreast compression element 300, thus increasing the likelihood ofripping. Further, sharp edges may also interfere with the x-rayradiation and cause discomfort for the patient. The smooth transitionsreduce these undesired effects. In an example, a “sharp edge” may bedefined as an intersection at a defined line or line segment of twoessentially planar surfaces. In another example, a sharp edge may bedefined as an edge between two surfaces where the angle between thetangent plane of the first surface and the tangent plane of the secondsurface is less than about 120 degrees at the location of intersectionbetween first and second surfaces. For example, although majority of thevarious surfaces discussed above all intersect at location substantiallyfree from sharp edges, the intersection between the back surface 310 andthe back surfaces need not be a smooth transition. For instance, in theexample depicted in FIGS. 3A-3I, the transition between the back surface310 and the left surface 304, the right surface 306, the top surface308, and the bottom surface 318 each include a sharp edge. As anexample, as depicted, the plane of the back surface 310 is perpendicularto the plane of the top surface 308.

FIG. 3I depicts the flexible material 314 removed from the remainder ofthe breast compression element 300 for clarity. In some examples,however, the flexible material 314 is not removable from the remainderof the compression element 300. For instance, where the flexiblematerial 311 is a shrink-wrap material, the shrinking process isperformed when the flexible material 314 is covering the remainder ofthe compression element 300. Thus, in such an example, the flexiblematerial 314 is not easily removed.

In examples where the flexible material 314 is a shrink-wrap material orother similar light-fitting material, the flexible material 314 may beapplied to the compression element 300 prior to conducting a breastimaging procedure. Heat is then applied to the compression element 300and the flexible material 314 to cause the flexible material to shrinkand increase the tension of the portion of the flexible material 314spanning the gap 316. In some examples, the heating process may occur ata time just prior to the breast imaging procedure in order to warm thebreast compression element 300 to increase patient comfort as the breastis compressed. Additionally, the flexible material 314 is advantageouslydisposable. As such, after use with a first patient, the flexiblematerial 314 may be removed and a new flexible material 314 may beapplied for a subsequent patient. This may eliminate the need to cleanor otherwise treat the surface of the breast compression element 300between patients.

FIG. 4A depicts a schematic view of an imaging system using the breastcompression element of FIGS. 3A-3I. FIG. 4B depicts a perspective viewof a breast imaging system of FIG. 4A and is described concurrently withFIG. 4A. In the depicted system, a patient's breast 410 is immobilizedfor x-ray imaging between two breast compression elements, namely abreast support platform 412 and a compression paddle 416. Platform 112can be the upper surface of a housing 414. Either one or both of theplatform 412 and the compression paddle 16 may be made in the shape ofthe of the breast compression element depicted in FIGS. 3A-3I. Platform412 and paddle 416 form a breast immobilizer unit 20 that is in a pathof an imaging beam 422 emanating from x-ray source 424. For instance,where the platform 412 incorporates the breast compression elementsdepicted in FIGS 3A-3I, a radiographic detector or image receptor 426may be incorporated into a hollow portion of the breast compressionelement. Beam 422 impinges on the image receptor 426 that is in housing414, which in some examples may be at least a portion of the breastcompression element. Immobilizer 420 and housing 414 are supported on anarm 428. X-ray source 424 is supported on an arm 430. For mammography,support arms 428 and 430 can rotate as a unit about an axis such as at430 a between different imaging orientations such as CC and MLO, so thatthe system can take a mammogram projection image at each orientation.Image receptor 426 remains in place relative to housing 414 while animage is taken. Immobilizer 420 releases breast 410 for movement of arms428 and 430 to a different imaging orientation. For tomosynthesis,support arm 428 stays in place, with breast 410 immobilized andremaining in place, while at least source support arm 430 rotates source424 relative to immobilizer 420 and breast 410 about an axis such as 30a. The system takes plural tomosynthesis projection images of breast 410at respective angles of beam 422 relative to breast 410. Concurrently,image receptor 426 may be tilted relative to breast platform 412 in syncwith the rotation of source support arm 430. The tilting can be throughthe same angle as the rotation of source 424, but may be through adifferent angle, selected such that beam 422 remains substantially inthe same position on image receptor 426 for each of the plural images.The tilting can be about an axis 432 a, which can but need not be in theimage plane of image receptor 426. A tilting mechanism 434, which alsois in housing 414 or is otherwise coupled with receptor 426, can driveimage receptor 426 in a tilting motion. Axes 430 a and 432 a extendleft-right as seen in FIG. 4A. For tomosynthesis imaging and/or CTimaging, breast platform 412 can be horizontal or can be at an angle tothe horizontal, e.g., at an orientation similar to that for conventionalMLO imaging in mammography. The system of FIGS. 4A-4B can be solely amammography system, a CT system, or solely a tomosynthesis system, or a“combo” system that can perform multiple forms of imaging. An example ofsuch a combo system is been offered by the assignee hereof under thetrade name Selenia Dimensions.

When the system is operated, image receptor 426 produces imaginginformation in response to illumination by imaging beam 422, andsupplies it to image processor 434 for processing to generate breastx-ray images. A fluid control unit 436 connects with the compressionpaddle to provide warm air into the compression paddle 416 to increasethe comfort of the patient, and/or heat or pressurize the flexiblematerial surrounding the paddle, as described heat. In an example, thefluid control unit 436 connects via a quick-release snap-on connection448. A system control and work station unit 438 controls the operationof the system and interacts with a user to receive commands and deliverinformation including processed-ray images.

Image processing with a compression paddle having a non-planarcompression surface, however, raises additional challenges due to theshape of the paddle For instance, due to the shape of the paddle beingnon-planar or have in a non-uniformity on the compression surface, thebreast is not compressed to a uniform thickness. Accordingly, radiationthat passes through the curved paddle and the compressed breast isattenuated differently. As a result bright spots and non-uniformity ofthe resultant image occurs. The prevent technology provides for asolution for processing an image when using a curved paddle to correctfor the differences in attenuations. As an example, FIG. 5A shows anuncorrected image of a breast impressed with a curved paddle, such asthose described herein or those cited in Publication No. WO 2014/176445,which is hereby incorporated herein by reference in its entirety. As canbe seen from the image, the upper portion of the breast appears darkerthan normal and the center of the breast, particularly towards the chestwall, appears brighter than normal. By using the image processingtechniques discussed herein, the image can be corrected to the correctedimage shown in FIG. 5B. As can be seen from the image in FIG. 5B, thebrightness appears more uniform and the underlying tissue composition ofthe can be more easily discerned.

In some examples, the image processing techniques of the presenttechnology involves generating a correction map for a particular curvedpaddle having a non-planar compression surface. The generation of thecorrection map may only need to be performed once for a particularcurved paddle shape and imaging system. For instance, the samecorrection map may be utilized for all systems of a given type using theparticular curved paddle. Once a correction map has been generated forthe particular curved paddle, the correction map can be applied to rawimage data or an image dataset taken of a breast compressed with theparticular curved paddle to generate a corrected image. The correctionmap may also be adjusted for a particular scan configuration, such astomosynthesis imaging, two-dimensional imaging, CT imaging,mediolateral-oblique imaging, craniocaudal (CC) imaging, or otherimaging configurations and orientations, including combinations thereof.

FIG. 6A depicts a method 600 for generating a correction map for imageprocessing for curved paddles. At operation 602, the paddle is filledwith a liquid such as water. For instance, the paddle may be hollow andhave an opening on the top of the paddle, among other positions, suchthat the paddle may be filled. For instance, the paddle may include arecess on at least a top portion of the paddle to receive the liquid.The recess may be generally open or may include an opening on a portionto access the recess. The recess may generally be on the top portion ofthe paddle such that the liquid may fill a portion which corresponds tothe compression surface. Depending on the paddle, certain connectionslots or other apertures in the paddle may need to be plugged such thatthe liquid does not flow out the paddle. For curved paddles that are nothollow, the paddle may be dipped in water in a substantially radiolucentcontainer. At operation 604, the paddle is placed on a substantiallyradiolucent surface proximate to the detector. For instance, the paddlemay be placed on a Lucite block having about generally a 4 centimeterthickness. In some examples, the substantially radiolucent surfacecovers the entire imaging area of the detector.

Radiation, such as x-ray radiation, is passed through the filled paddleand the substantially radiolucent surface at operation 606. Theradiation is then detected by the detector at operation 608. Theemission and detection of radiation may occur during a standard 2Dimaging mode. In some examples, an auto-kV mode may be used, but othermodes may also be suitable. The radiation used for calibration orgeneration of the correction map may be at one or more of a scoutexposure, a full mammographic exposure, or one or more tomosynthesisexposures. An image, or image data, is the generated form the detectedradiation at operation 610. The image generated is indicative of thecurved paddle shape. An example image produced at operation 610 isdepicted in FIG. 6B.

From the image data produced in operation 610, an average pixel value isdetermined at operation 612. The average pixel value may be determinedacross the entire image. Based at least one average pixel value, thecorrection map is generated at operation 614. The correction map may begenerated by dividing the pixel values of the image data generated inoperation 610 by the average pixel value determined in operation 612 togenerate a normalized correction map. In some examples, the correctionmap is further modified by generating a series of polynomial fits torepresent the correction map. For instance, the correction map may beconsidered to be a matrix, where the elements of the matric representcorrection values for a corresponding pixel of the detector. Eachelement of the matrix includes a value for scaling a brightness value ofthe corresponding pixel of the detector. Similarly, the correction mapmay also be considered to be a set of columns (x) of pixels or pointsand a rows (y) of pixels or points. In such an example, for each column(x), pixels along the rows (y) are selected. In selecting the pixels,some pixels may skipped, such as skipping by ten pixels for eachselection. The values for the selected pixels are then in to apolynomial function, such as a 4th order polynomial. For each of they-values, the polynomial fitting may be used to generate a fitted imageor a fitted correction map. The fitted correction map may also besmoothed using an averaging technique, such as a boxcar averagingmethod. In addition, the smoothed, fitted correction map may be scaleddown. In some examples, the scaling may be by a factor of 4 and may bedone using decimation (e.g., skipping points). Other seating factors arecontemplated. The scaled, smoothed, and fitted correction map may thenbe stored as a final correction map to be used in image processing. Byfitting the correction map to a polynomial, image noise or other localirregularities are effectively removed from the final correction map.Once the correction map has been generated, it can be used to correctimage data taken using the curved paddle for which the correction mapwas generated. For example, the image shown in FIG. 6C is a correctedversion of the image shown in FIG. 6B using the correction map generatedfrom the image in FIG. 6B.

FIG. 7 depicts a method 700 for image processing for curved paddlesutilizing a correction map, such as the one generated by method 600depicted in FIG. 6A. At operation 702, image data is received. The imagedata may be received from detector of the imaging system. At operation704, a correction map associated with the compression paddle is used tocompress the breast during imaging. In some examples, the correction mapmay be stored locally or remotely from the imaging system. Thecorrection map may be further altered or corrected prior to its use incorrecting the image data received in operation 702. For example, thecorrection map may be seated based on an image size for the image datareceived in operation 702. The scaling may be to upscale the correctionmap to the current image size using a linear interpolation technique.The correction map may also be smoothed using an averaging technique,such as a boxcar averaging technique. The correction map may also bemodified by applying a squeeze factor. The squeeze factor is anadjustment to the correction map that is paddle dependent. The squeezefactor allows for adjustment of the magnitude of the correction providedby the correction map. The correction map may also be modified tocorrect for a projection angle and a paddle shift. Such a correctionshifts the correction map depending on the projection angle and theactual paddle shift. In addition, the correction map may also bemodified to correct for magnification. For example, the correction mapmay be modified based on the paddle height used for imaging as comparedto the paddle height used during calibration. For instance, in exampleswhere a 4 cm Lucite block is used as the substantially radiolucentsurface in operation 604 of the calibration method 400, the calibrationheight is 4 cm. The height may be measured to any point on the paddle aslong as the measurement is consistent when comparing heights.

At operation 706, the image data received at operation 702 is correctedbased on the correction map accessed in operation 704. In some examples,the image data is corrected based on the correction map as modifiedaccording to the techniques discussed above. The image data may becorrected or a pixel-by-pixel basis, the image may be corrected bymultiplying or dividing the image data by the correction map. Forinstance, each pixel of the image data may be multiplied or divided bythe corresponding pixel value in the correction map. The correction tothe image data may also be a correction to the raw image data prior togenerating an actual image of the breast being imaged. At operation 708,a corrected image is generated from the corrected image data. In someexamples, such as with breast CT and/or tomosynthesis techniques, thecorrected image may be part of an image dataset that includes a seriesof images. Generating the corrected image may also include displayingthe corrected image on a display screen or other medium for viewing andanalysis by a physician or technician.

In some instances, further correction to the image data may be desiredfor image areas near the chest wall, such as about 2 cm from the chestwall. For example, while the above corrections work well for imagingportions of the breast in contact with the paddle, the corrections maybe further improved for portions of the breast not in contact with thepaddle. When the breast is not in contact with the paddle, an air gap isformed between the breast and the paddle. The x-ray attenuation istherefore different for portions of the breast in contact with thepaddle and portions of the breast not in contact with the paddle.Portions of the breast not in contact with the paddle generally occurnear the chest wall. The additional correction for imaging the breastportions not in contact with the paddle may be referred to as an airarea correction (AAC).

The AAC may be a further correction in addition to already utilizedcorrections or other image processing techniques to further helpvisualize the breast. As an example, the AAC may be a further correctionto at least one of a multiscale image decomposition technique utilizedin processing the image and skin line detection of correctiontechniques. For instance, the skin line correction may be utilized toequalize the pixel values near the skin edge in order to improvevisualization of the breast near the skin line. The AAC may be anadditional correction near the chest wall to correct for the brightnesschanges due to the air gap between the paddle and the breast. As anexample, the AAC may utilize a correction based on the differencebetween the pixel value and a threshold value. For instance, theadjustment value may be based on a value, representing the differencebetween the pixel value and a threshold value, multiplied by a slopevalue at one or more image decomposition scales. In addition, the slopemay be represented by a weighting factor function based on the pixellocation. After the AAC correction according to the above techniques,the attenuation in the small local vertical area near the chest wall iscorrected and the final processed images do not appear as having anon-uniformity, such as a slightly dark area, near the chest wall.

FIG. 8 depicts a method for image processing for a paddle providinginconsistent compression. For example, with a paddle having a flexibleelement, such as breast compression element 300 discussed above, eachbreast will not be compressed in the same manner. Accordingly,additional improvements may be made in addition to the one-timecalibration map solution discussed above. For example, correction to theimages taken with a paddle providing inconsistent compression may bedetermined on the fly for each image taken of the breast.

At operation 802, image data is received for an image of the breast. Theimage data may be received from a detector. At operation 804, pixelvalues in the image data are identified. In some examples, an averagepixel value may also be determined. Based on the pixel values in theimage data, a low frequency correction is determined at operation 806.The low frequency collection may be generated in the form of acorrection map or a low frequency function. The low frequency correctionis to correct for the background variations in brightness, while notobscuring any of the higher detail elements of the image, such asvascular elements or other tissue composition of the breast. Based onthe low frequency correction, a corrected image may then be generated inoperation 808.

FIG. 9 depicts one example of a suitable computing device 1400 that maybe coupled to the scanning systems discussed herein. The computingdevice 1400 is a suitable operating environment in which one or more ofthe present examples can be implemented. This operating environment maybe incorporated directly into a scanning system, or may be incorporatedinto a computer system discrete from, but used to control or processdata from the scanning systems described herein. This is only oneexample of a suitable operating environment and is not intended tosuggest any limitation as to the scope of use or functionality. Otherwell-known computing systems, environments, and/or configurations thatcan be suitable for use include, but are not limited to, personalcomputers, server computers, hand-held or laptop devices, multiprocessorsystems, microprocessor-based systems, programmable consumer electronicssuch as smart phones, network PCs, minicomputers, mainframe computers,tablets, distributed computing environments that include any of theabove systems or devices, and the like.

In its most basic configuration, operating environment 1400 typicallyincludes at least one processing unit 1402 and memory 1404. Depending onthe exact configuration and type of computing device, memory 1404(storing, among other things, instructions to perform the measurementacquisition, processing and visual representation generation methodsdisclosed herein) can be volatile (such as RAM), non-volatile (such asROM, flash memory, etc.), or some combination of the two. This mostbasic configuration is illustrated in FIG. 9 by dashed line 1406.Further, environment 1400 can also include storage devices (removable,1408, and/or non-removable, 1410) including, but not limited to,solid-state devices, magnetic or optical disks, or tape. Similarly,environment 1400 can also have input device(s) 1414 such as touchscreens, keyboard, mouse, pen, voice input, etc., and/or outputdevice(s) 1416 such as a display, speakers, printer, etc. Also includedin the environment can be one or more communication connections 1412,such as LAN, WAN, point to point, Bluetooth, RF, etc.

Operating environment 1400 typically includes at least some form ofcomputer readable media. Computer readable media can be any availablemedia that can be accessed by processing unit 1402 or other devicescomprising the operating environment. By way of example, and notlimitation, computer readable media can comprise computer storage mediaand communication media. Computer storage media includes volatile andnonvolatile, removable and non-removable media implemented in any methodor technology for storage of information such as computer readableinstructions, data structures, program modules or other data. Computerstorage media includes, RAM, ROM, EEPROM, flash memory or other memorytechnology, CD-ROM, digital versatile disks (DVD) or other opticalstorage, magnetic cassettes, magnetic tape, magnetic disk storage orother magnetic storage devices, solid state storage, or any othertangible and non-transitory medium which can be used to store thedesired information.

Communication media embodies computer readable instructions, datastructures, program modules, or other data in a modulated data signalsuch as a carrier wave or other transport mechanism and includes anyinformation delivery media. The term “modulated data signal” means asignal that has one or more of its characteristics set or changed insuch a manner as to encode information in the signal. By way of example,and not limitation, communication media includes wired media such as awired network or direct-wired connection, and wireless media such asacoustic, RF, infrared and other wireless media. Combinations of the anyof the above should also be included within the scope of computerreadable media.

The operating environment 1400 can be a single computer operating in anetworked environment using logical connections to one or more remotecomputers. The remote computer can be a personal computer, a server, arouter, a network PC, a peer device or other common network node, andtypically includes many or all of the elements described above as wellas others not so mentioned. The logical connections can include anymethod supported by available communications media. Such networkingenvironments are commonplace in hospitals, offices, enterprise-widecomputer networks, intranets and the Internet.

In some examples, the components described herein comprise such modulesor instructions executable by computer system 1400 that can be stored oncomputer storage medium and other tangible mediums and transmitted incommunication media. Computer storage media includes volatile andnon-volatile, removable and non-removable media implemented in anymethod or technology for storage of information such as computerreadable instructions, data structures, program modules, or other data.Combinations of any of the above should also be included within thescope of readable media. In some examples, computer system 1400 is partof a network that stores data in remote storage media for use by thecomputer system 1400.

FIG. 10 is an example of a network 1500 in which the various systems andmethods disclosed herein may operate. In examples, a client device, suchas client device 1502, may communicate with one or more servers, such asservers 1504 and 1506, via a network 1508. In examples, a client devicemay be a laptop, a personal computer, a smart phone, a PDA, a netbook,or any other type of computing device, such as the computing device inFIG. 9 . In examples, servers 1504 and 1506 may be any type of computingdevice, such as the computing device illustrated in FIG. 9 . Network1508 may be any type of network capable of facilitating communicationsbetween the client device and one or more servers 1504 and 1506.Examples of such networks include, but are not limited to, LANs, WANs,cellular networks, and/or the Internet.

In examples, processing of data and performance of the methods describedherein may be accomplished with the use of one or more server devices.For example, in one example, a single server, such as server 1504 may beemployed to assist in processing data and performing the methodsdisclosed herein. Client device 1502 may interact with server 1504 vianetwork 1508. In further examples, the client device 1502 may alsoperform functionality disclosed herein, such as scanning and processingdata, which can then be provided to servers 1504 and/or 1506.

In alternate examples, the methods disclosed herein may be performedusing a distributed computing network, or a cloud network. In suchexamples, the methods disclosed herein may be performed by two or moreservers, such as servers 1504 and 1506. Although a particular networkexample is disclosed herein, one of skill in the art will appreciatethat the systems and methods disclosed herein may be performed usingother types of networks and/or network configurations. Further, the datasent to the servers and received from the servers may be encrypted. Thedata may also be stored in an encrypted manner both locally and on theservers.

This disclosure described some examples of the present technology withreference to the accompanying drawings, in which only some of thepossible examples were shown. Other aspects can, however, be embodied inmany different forms and should not be construed as limited to theexamples set forth herein. Rather, these examples were provided so thatthis disclosure was thorough and complete and fully conveyed the scopeof the possible examples to those skilled in the art.

Although specific examples were described herein, the scope of thetechnology is not limited to those specific examples. One skilled in theart will recognize other examples or improvements that are within thescope of the present technology. Therefore, the specific structure,acts, or media are disclosed only as illustrative examples. Examplesaccording to the technology may also combine elements or components ofthose that are disclosed in general but not expressly exemplified incombination, unless otherwise stated herein. The scope of the technologyis defined by the following claims and any equivalents therein.

What is claimed is:
 1. A system for imaging a breast, the systemcomprising: an x-ray radiation source; a compression paddle, wherein thecompression paddle is configured to have a non-planar compressionsurface during compression of the breast; a detector configured todetect x-ray radiation emitted from the x-ray radiation source afterpassing through the compression paddle and the breast, wherein thedetector includes a plurality of pixels; and a memory and a processoroperatively connected to the detector, wherein the memory storesinstructions that, when executed by the processor, perform a set ofoperations, the operations comprising: receiving image data from thedetector; accessing a correction map for the compression paddle;correcting the image data based on the correction map to generatecorrected image data; and generating an image of the breast based on thecorrected image data.
 2. The system of claim 1, wherein the operationsfurther comprise at least two of the following operations: upscaling thecorrection map based on an image size for the image; modifying thecorrection map by applying a squeeze factor; modifying the correctionmap for a projection angle and a paddle shift; and modifying thecorrection map based on a magnification.
 3. The system of claim 2,wherein modifying the correction map based on magnification is based atleast in part on a height of the compression paddle.
 4. The system ofclaim 1, wherein the correction map is represented as a matrix, whereinelements of the matrix represent correction values for a correspondingpixel of the detector.
 5. The system of claim 4, wherein the elements ofthe matrix include values for scaling a brightness value of thecorresponding pixel of the detector.
 6. The system of claim 1, whereincorrecting the image data includes correcting the image data on apixel-by-pixel level.
 7. The system of claim 1, wherein the correctionmap is generated by a process comprising: filling the compression paddlewith a liquid to create a filled paddle; placing the filled paddle on asubstantially radiolucent surface, wherein the radiolucent surfacecovers an imaging area of the detector; passing the x-ray radiationthrough the filled paddle and substantially radiolucent surface;detecting the x-ray radiation passed through the filled paddle andsubstantially radiolucent surface; generating a correction image basedon the detected x-ray radiation; identifying an average pixel value overthe correction image; and generating the correction map by dividing eachpixel in the correction image by the average pixel value.
 8. The systemof claim 7, wherein generating the correction map further comprisesgenerating a series of polynomial fits to represent the correction map.9. A method for imaging a breast, the method comprising: compressing thebreast with a compression paddle such that, when the breast iscompressed, the compression paddle has a non-planar compression surface;while the breast is compressed, emitting x-ray radiation from an x-rayradiation source; detecting, by a detector, the emitted x-ray radiationafter the emitted x-ray radiation has passed through the breast and thecompression paddle; receiving, from the detector, image data based onthe detected x-ray radiation; accessing a correction map for thecompression paddle; correcting the image data based on the correctionmap to generate corrected image data; and generating an image of thebreast based on the corrected image data.
 10. The method of claim 9,further comprising at least two of the following operations: upscalingthe correction map based on an image size for the image; modifying thecorrection map by applying a squeeze factor; modifying the correctionmap for a projection angle and a paddle shift; and modifying thecorrection map based on a magnification.
 11. The method of claim 9,wherein the correction map comprises a polynomial fit to represent thecorrection map.
 12. The method of claim 9, wherein the correction map isrepresented as a matrix, wherein elements of the matrix representcorrection values for a corresponding pixel of the detector.
 13. Themethod of claim 9, wherein the compression surface includes a flexiblematerial.
 14. The method of claim 13, wherein the flexible material is athin-film material.
 15. The method of claim 9, further comprising:subsequent to receiving the image data, generating the correction map tocorrect for background variations in brightness.
 16. The method of claim15, wherein generating the correction map includes determining anaverage pixel value in the image data.
 17. The method of claim 15,wherein the correction map is a low-frequency correction.
 18. The methodof claim 15, wherein the correction map comprises a polynomial fit torepresent the correction map.
 19. The method of claim 15, wherein thecompression surface includes a flexible material.
 20. The method ofclaim 19, wherein the flexible material is a thin-film material.